The present invention is directed to a piezo-electric transducer having electrodes that adhere well both to ceramic as well as to plastics and is also directed to a method for the manufacture thereof.
European Patent Application No. 0 154 706 discloses a piezo-electric air-ultrasound transducer. The electro-acoustic transducer is composed of ceramic lamellae that are arranged at defined spacings in planes parallel to one another. The interspaces formed by the spacings are filled with a suitable, shape-stable material.
In order to create a sandwich-like transducer structure, the individual ceramic lamellae must be connected to one another or, respectively, to the plastic filling the interspaces. The connection between the lamellae and/or plastic must also be durable. For example, the lamellae and/or plastic can be glued together.
It is known in prior art to use nickel electrodes. Nickel electrodes can be produced easily and inexpensively by chemical deposition on the ceramic surface. This type of electrode, however, exhibits poor adhesion to plastics and is therefore difficult to join thereto. But, if a sandwich structure is to be constructed, it is necessary for the electrode to be joined to plastic.
Silver electrodes (stoving silver) can be used as an alternative to nickel electrodes. Silver electrodes exhibit good adhesion to plastic, but, silver electrodes greatly increase the manufacturing costs of the product.
There is therefore a need for an economic electrode material that can adhere to ceramic and plastic.